The present invention relates to a ureter drainage device comprising a ureteral catheter, a sliding hose to be coupled to the proximal end of the ureteral catheter, and a control hose to be mounted over the sliding hose.
Ureteral catheters, which are also referred to as dual J-stents or in-dwelling ureter splints, are hose-shaped aids for discharge of the urine from the renal pelvis into the urinary bladder in cases where the ureter is not sufficiently permeable anymore. The ureteral catheters which are presently in widespread use have both of their ends formed with involutions. The involution in the renal pelvis has a smaller diameter while the involution of the bladder has a larger diameter. For placing the catheters through the urethra and the bladder, use is made of a cystoscope. The involutions of the catheter have to be straightened into a linear orientation so that the catheter will fit through the cystoscope working channel. This straightening of the catheter is carried out by means of a guide wire. If the tip of the catheter comprises a closed cap, the guide wire is set from the bladder-side end. If the guide wire is already arranged in the ureter, the straightening and subsequent upward shifting of the catheter into the renal pelvis is made possible in that the catheter tip is open and of an integral conical shape. Since the ureteral catheter serves for internal splintage and its draining end region extends only to a position within the bladder, the ureteral catheter remaining within the patient""s body has to be shifted off the guide wire. This is accomplished by use of a sliding hose.
In certain cases where the ureter follows a considerably winding course or in case of very narrow ureter stenoses, a firm but detachable connection between the urethral catheter and the sliding hose would be suitable because such a connection would allow not only for shifting but also for pulling and rotating movements of the catheter.
U.S. Pat. No. 4,963,129 describes a ureter drainage device with shifting hose. The shifting hose connects to the urethral catheter via a coupling device comprising two interengaging coupling elements. Securement of the coupling device in the engaged position is performed by the guide wire. When the guide wire is pulled out, the sliding hose is detached from the ureter hose.
EP 0 752 251 A1 describes a ureter drainage device wherein the proximal end of the ureteral catheter is connected to a sliding hose through frictional engagement. Extending in the sliding hose is a control hose adapted to be advanced for releasing the frictional engagement and separating the ureteral catheter from the sliding hose.
It is an object of the invention to provide a ureter drainage device wherein the ureteral catheter is reliably held in position on the sliding hose for shifting, pulling and rotating movements during advancement, irrespective of whether a guide wire has been inserted.
In the ureter drainage device according to the instant invention, the ureteral catheter and the sliding hose comprise mutually engaging coupling elements. At least one of coupling element, provided on the sliding hose, is radially outwardly biased in the release direction and is retained in the engagement position by the control hose covering said one coupling element.
The invention allows for the use of the present catheter placement techniques such as the Seldinger technique and the retrograde technique. Using the invention, the decoupling of the ureteral catheter from the sliding hose can be performed easily and by application of a defined force. This is effected by two mutually engaging coupling members which are held in engagement by the outer control hose. This arrangement obviates the need for an internal guide wire for fixing the two members. At least one of the coupling elements of the sliding hose is subjected to an inherent radial outward bias in its release direction while being retained by the sliding hose so as to remain engaged with the proximal end of the ureteral catheter. In this manner, pulling forces as well as shifting and rotational forces can be transmitted. To release the connection, the control hose is withdrawn on the sliding hose, causing the coupling element to spread apart under the effect of the bias and thus to release the ureteral catheter.
According to a preferred embodiment of the invention, it is provided that the coupling element of the sliding hose comprises at least one distally projecting leg with a hook provided on its end, and that the coupling element of the ureteral catheter is formed with a recess for receiving the hook.
Preferably, the coupling element of the sliding hose is formed as a barb which, when sliding on the ureteral catheter, will snap into a locked position in a recess of the catheter. This barb is of a saw-tooth design comprising an inclined flank and an upright flank.
According to another preferred embodiment of the invention, there is provided a handling means comprising two grip portions arranged for displacement in the longitudinal direction and being biased to move away from each other in the longitudinal direction. One of the grip portions is connected to the sliding hose and the other grip portion is connected to the control hose. The grip portions are pressed away from each other by a spring means, with the control hose being urged into the advanced position to cover and lock the coupling device. When the grip portion connected to the control hose is retracted against the spring force, the control hose will release its grip on the coupling device and thus permit disengagement thereof. This allows for easy handling and even for single-handed operation of the drainage device for disengagement of the coupling device.